Files
tidb/perfschema/perfschema.go
2017-04-29 10:59:02 -05:00

89 lines
2.4 KiB
Go

// Copyright 2016 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
package perfschema
import (
"reflect"
"github.com/juju/errors"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/model"
"github.com/pingcap/tidb/table"
"github.com/pingcap/tidb/terror"
)
var (
errInvalidPerfSchemaTable = terror.ClassPerfSchema.New(codeInvalidPerfSchemaTable, "invalid perfschema table")
errInvalidTimerFlag = terror.ClassPerfSchema.New(codeInvalidTimerFlag, "invalid timer flag")
)
// StatementInstrument defines the methods for statement instrumentation points
type StatementInstrument interface {
RegisterStatement(category, name string, elem interface{})
StartStatement(sql string, connID uint64, callerName EnumCallerName, elem interface{}) *StatementState
EndStatement(state *StatementState)
}
// PerfSchema defines the methods to be invoked by the executor
type PerfSchema interface {
// StatementInstrument is for statement instrumentation only.
StatementInstrument
// GetDBMeta returns db info for PerformanceSchema.
GetDBMeta() *model.DBInfo
// GetTable returns table instance for name.
GetTable(name string) (table.Table, bool)
}
type perfSchema struct {
store kv.Storage
dbInfo *model.DBInfo
tables map[string]*model.TableInfo
mTables map[string]table.Table // Memory tables for perfSchema
stmtHandles []int64
stmtInfos map[reflect.Type]*statementInfo
}
var (
_ PerfSchema = (*perfSchema)(nil)
// perfschema is disabled by default to avoid performance consuming.
enablePerfSchema = false
)
// EnablePerfSchema enables perfschema.
func EnablePerfSchema() {
enablePerfSchema = true
}
// NewPerfHandle creates a new perfSchema on store.
func NewPerfHandle() (PerfSchema, error) {
schema := &perfSchema{}
err := schema.initialize()
if err != nil {
return nil, errors.Trace(err)
}
schema.registerStatements()
return schema, nil
}
// perfschema error codes.
const (
codeInvalidPerfSchemaTable terror.ErrCode = 1
codeInvalidTimerFlag = 2
)